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Pinheiro Dos Santos TJ, Orcan-Ekmekci B, Chapman WG, Singer PM, Asthagiri DN. Theory and modeling of molecular modes in the NMR relaxation of fluids. J Chem Phys 2024; 160:064108. [PMID: 38341792 DOI: 10.1063/5.0180040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/18/2024] [Indexed: 02/13/2024] Open
Abstract
Traditional theories of the nuclear magnetic resonance (NMR) autocorrelation function for intra-molecular dipole pairs assume a single-exponential decay, yet the calculated autocorrelation of realistic systems displays a rich, multi-exponential behavior, resulting in anomalous NMR relaxation dispersion (i.e., frequency dependence). We develop an approach to model and interpret the multi-exponential intra-molecular autocorrelation using simple, physical models within a rigorous statistical mechanical development that encompasses both rotational diffusion and translational diffusion in the same framework. We recast the problem of evaluating the autocorrelation in terms of averaging over a diffusion propagator whose evolution is described by a Fokker-Planck equation. The time-independent part admits an eigenfunction expansion, allowing us to write the propagator as a sum over modes. Each mode has a spatial part that depends on the specified eigenfunction and a temporal part that depends on the corresponding eigenvalue (i.e., correlation time) with a simple, exponential decay. The spatial part is a probability distribution of the dipole pair, analogous to the stationary states of a quantum harmonic oscillator. Drawing inspiration from the idea of inherent structures in liquids, we interpret each of the spatial contributions as a specific molecular mode. These modes can be used to model and predict the NMR dipole-dipole relaxation dispersion of fluids by incorporating phenomena on the molecular level. We validate our statistical mechanical description of the distribution in molecular modes with molecular dynamics simulations interpreted without any relaxation models or adjustable parameters: the most important poles in the Padé-Laplace transform of the simulated autocorrelation agree with the eigenvalues predicted by the theory.
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Affiliation(s)
| | | | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
| | - Philip M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
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Gupta S, Elliott JR, Anderko A, Crosthwaite J, Chapman WG, Lira CT. Current Practices and Continuing Needs in Thermophysical Properties for the Chemical Industry. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.2c03153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- Sumnesh Gupta
- The Dow Chemical Company, 1254 Enclave Parkway, Houston, Texas 77077, United States
| | - J. Richard Elliott
- Chemical, Biomolecular, and Corrosion Engineering Department, University of Akron, Akron, Ohio 44325-3906, United States
| | - Andrzej Anderko
- OLI Systems, Inc., 2 Gatehall Drive, Suite 1D, Parsippany, New Jersey 07054, United States
| | - Jacob Crosthwaite
- The Dow Chemical Company, 1897 Building, Midland, Michigan 48667, United States
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering Department, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Carl T. Lira
- Chemical Engineering & Materials Science, Michigan State University, East Lansing, Michigan 48824-2288, United States
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Valiya Parambathu A, Chapman WG, Hirasaki GJ, Asthagiri D, Singer PM. Effect of Nanoconfinement on NMR Relaxation of Heptane in Kerogen from Molecular Simulations and Measurements. J Phys Chem Lett 2023; 14:1059-1065. [PMID: 36693239 DOI: 10.1021/acs.jpclett.2c03699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Kerogen-rich shale reservoirs will play a key role during the energy transition, yet the effects of nanoconfinement on the NMR relaxation of hydrocarbons in kerogen are poorly understood. We use atomistic MD simulations to investigate the effects of nanoconfinement on the 1H NMR relaxation times T1 and T2 of heptane in kerogen. In the case of T1, we discover the important role of confinement in reducing T1 by ∼3 orders of magnitude from that of bulk heptane, in agreement with measurements of heptane dissolved in kerogen from the Kimmeridge Shale, without any models or free parameters. In the case of T2, we discover that confinement breaks spatial isotropy and gives rise to residual dipolar coupling which reduces T2 by ∼5 orders of magnitude from the value for bulk heptane. We use the simulated T2 to calibrate the surface relaxivity and thence predict the pore-size distribution of the organic nanopores in kerogen, without additional experimental data.
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Affiliation(s)
- Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware19716, United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
| | - George J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
| | - Dilipkumar Asthagiri
- Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee37830-6012, United States
| | - Philip M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
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Lu J, González de Castilla A, Müller S, Xi S, Chapman WG. Dualistic Role of Alcohol in Micelle Formation and Structure from iSAFT Based Density Functional Theory and COSMOplex. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.2c03507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jinxin Lu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas77005, United States
| | | | - Simon Müller
- Institute of Thermal Separation Processes, Hamburg University of Technology, Hamburg21073, Germany
| | - Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas77005, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas77005, United States
- Institute of Thermal Separation Processes, Hamburg University of Technology, Hamburg21073, Germany
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Chapman WG, Fouad WA. Beyond Flory–Huggins: Activity Coefficients from Perturbation Theory for Polar, Polarizable, and Associating Solvents to Polymers. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c02896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas77005, United States
| | - Wael A. Fouad
- Department of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran31261, Saudi Arabia
- Interdisciplinary Research Center for Refining & Advanced Chemicals, King Fahd University of Petroleum and Minerals, Dhahran31261, Saudi Arabia
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Adhikari RS, Parambathu AV, Chapman WG, Asthagiri DN. Hydration Free Energies of Polypeptides from Popular Implicit Solvent Models versus All-Atom Simulation Results Based on Molecular Quasichemical Theory. J Phys Chem B 2022; 126:9607-9616. [PMID: 36354351 DOI: 10.1021/acs.jpcb.2c05725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Calculating the hydration free energy of a macromolecule in all-atom simulations has long remained a challenge, necessitating the use of models wherein the effect of the solvent is captured without explicit account of solvent degrees of freedom. This situation has changed with developments in the molecular quasi-chemical theory (QCT)─an approach that enables calculation of the hydration free energy of macromolecules within all-atom simulations at the same resolution as is possible for small molecular solutes. The theory also provides a rigorous and physically transparent framework to conceptualize and model interactions in molecular solutions and thus provides a convenient framework to investigate the assumptions in implicit solvent models. In this study, we compare the results using molecular QCT versus predictions from EEF1, ABSINTH, and GB/SA implicit solvent models for polyglycine and polyalanine solutes covering a range of chain lengths and conformations. The hydration free energies or the differences in hydration free energies between conformers obtained from the implicit solvent models do not agree with explicit solvent results, with the deviations being largest for the group additive EEF1 and ABSINTH models. GB/SA does better in capturing the qualitative trends seen in explicit solvent results. Analysis founded on QCT reveals the critical importance of the cooperativity of hydration that is inherent in the hydrophilic and hydrophobic contributions to hydration─physics that is not well captured in additive models but somewhat better accounted for by means of a dielectric in the GB/SA approach.
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Affiliation(s)
- Rohan S Adhikari
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas77005, United States
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware19711, United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas77005, United States
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Affiliation(s)
- Carl T. Lira
- Chemical Engineering & Materials Science, Michigan State University, East Lansing, Michigan48824, United States
| | - J. Richard Elliott
- Chemical, Biomolecular, and Corrosion Engineering Department, University of Akron, Akron, Ohio44325-3906, United States
| | - Sumnesh Gupta
- The Dow Chemical Company, 1254 Enclave Parkway, Houston, Texas77077, United States
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering Department, Rice University, 6100 Main Street, Houston, Texas77005, United States
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Kamil A, Fouad WA, Gupta SK, Chapman WG. Phase Equilibrium of Cross-Associating Mixtures Using Association Theory-Based Equation of State. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c01707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ahsan Kamil
- Department of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Wael A. Fouad
- Department of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Refining & Advanced Chemicals, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Sumnesh K. Gupta
- The Dow Chemical Company, 1254 Enclave Parkway, Houston, Texas 77077, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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Alajmi MM, Sisco CJ, Abutaqiya MIL, Vargas FM, Chapman WG. Extension of Cubic-Plus-Chain Equation of State: Incorporating Short-Range Soft Repulsion for Nonassociating Mixtures. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c00902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohammed M. Alajmi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- Chemical Engineering Department, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait
| | | | | | - Francisco M. Vargas
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- ENNOVA LLC, Stafford, Texas 77477, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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Valiya Parambathu A, Pinheiro Dos Santos TJ, Chapman WG, Asthagiri DN. Comment on "Calculation of Solid-Fluid Interfacial Free Energy with Consideration of Solid Deformation by Molecular Dynamics". J Phys Chem A 2022; 126:1782-1783. [PMID: 35213157 DOI: 10.1021/acs.jpca.1c07474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Walter G Chapman
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Dilipkumar N Asthagiri
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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11
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Xi S, Zhu Y, Lu J, Chapman WG. Block copolymer self-assembly: Melt and solution by molecular density functional theory. J Chem Phys 2022; 156:054902. [DOI: 10.1063/5.0069883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
| | - Yiwei Zhu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
| | - Jinxin Lu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
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Pinheiro dos Santos TJ, Valiya Parambathu A, Fraenza C, Walsh C, Greenbaum SG, Chapman WG, Asthagiri D, Singer PM. Thermal and concentration effects on 1H NMR relaxation of Gd3+ aqua using MD simulations and measurements. Phys Chem Chem Phys 2022; 24:27964-27975. [DOI: 10.1039/d2cp04390d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gadolinium-based contrast agents are key in clinical MRI for enhancing the longitudinal NMR relativity (r1) of hydrogen nuclei (1H) in water and improving the contrast among different tissues. The importance...
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Affiliation(s)
- Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Wael A. Fouad
- Department of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Refining & Advanced Chemicals, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
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14
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Singer PM, Valiya Parambathu A, Wang X, Asthagiri D, Chapman WG, Hirasaki GJ, Fleury M, Ranguelova K. Correction to "Elucidating the 1H NMR Relaxation Mechanism in Polydisperse Polymers and Bitumen Using Measurements, MD Simulations, and Models". J Phys Chem B 2021; 125:11338-11339. [PMID: 34609864 DOI: 10.1021/acs.jpcb.1c07950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Singer PM, Parambathu AV, Pinheiro Dos Santos TJ, Liu Y, Alemany LB, Hirasaki GJ, Chapman WG, Asthagiri D. Predicting 1H NMR relaxation in Gd 3+-aqua using molecular dynamics simulations. Phys Chem Chem Phys 2021; 23:20974-20984. [PMID: 34518855 DOI: 10.1039/d1cp03356e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomistic molecular dynamics simulations are used to predict 1H NMR T1 relaxation of water from paramagnetic Gd3+ ions in solution at 25 °C. Simulations of the T1 relaxivity dispersion function r1 computed from the Gd3+-1H dipole-dipole autocorrelation function agree within ≃8% of measurements in the range f0 ≃ 5 ↔ 500 MHz, without any adjustable parameters in the interpretation of the simulations, and without any relaxation models. The simulation results are discussed in the context of the Solomon-Bloembergen-Morgan inner-sphere relaxation model, and the Hwang-Freed outer-sphere relaxation model. Below f0 ≲ 5 MHz, the simulation overestimates r1 compared to measurements, which is used to estimate the zero-field electron-spin relaxation time. The simulations show potential for predicting r1 at high frequencies in chelated Gd3+ contrast-agents used for clinical MRI.
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Affiliation(s)
- Philip M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA.
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA.
| | | | - Yunke Liu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA.
| | - Lawrence B Alemany
- Shared Equipment Authority and Department of Chemistry, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - George J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA.
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA.
| | - Dilip Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA.
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Abstract
Patchy colloids can be modeled as hard spheres with directional conical association sites. A variety of physical phenomena have been discovered in the patchy colloid system due to its short range and directional interactions. In this work, we combined a cluster distribution theory with generalized Flory and Stockmayer percolation theory to investigate the interplay between phase behavior and percolation for a binary patchy colloid system. The binary patchy colloid system consists of solute molecules with spherically symmetric bonding sites and solvents with two singly bondable sites. Wertheim's first order thermodynamic perturbation theory (TPT1) has been widely applied to the patchy colloids system and it has been combined with percolation theory to study the percolation threshold. However, due to assumptions behind TPT1, it will lose accuracy for a system in which particles have multiple association sites or multiply bondable sites. A recently proposed cluster distribution theory accurately models association at sites that can form multiple bonds. In this work, we investigate the comparison among cluster distribution theory, TPT1, and Monte Carlo simulation for the bonding states of this binary system in which cluster distribution theory shows excellent agreement with Monte Carlo simulation, while TPT1 has a large deviation with the simulation. Cluster distribution theory was further combined with the Flory and Stockmayer percolation theory to investigate the interplay between phase behavior and percolation threshold. We found that the reduced density and the relative bonding strength of solvent-solvent association and solute-solvent association are key factors for the phase behavior and percolation. Percolation can form at low density and low temperature in the vapor phase of this binary system, where the star-like molecules with 12 long branches formed.
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Affiliation(s)
- Yiwei Zhu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
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Haghmoradi A, Ballal D, Fouad WA, Wang L, Chapman WG. Combination of monovalent and divalent sites on an associating species: Application to water. AIChE J 2021. [DOI: 10.1002/aic.17146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Amin Haghmoradi
- Department of Chemical and Biomolecular Engineering Rice University Houston Texas USA
| | - Deepti Ballal
- Department of Chemical and Biomolecular Engineering Rice University Houston Texas USA
| | - Wael A. Fouad
- Department of Chemical Engineering King Fahd University of Petroleum and Minerals Dhahran Saudi Arabia
| | - Le Wang
- Department of Chemical and Biomolecular Engineering Rice University Houston Texas USA
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering Rice University Houston Texas USA
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Khemka Y, Abutaqiya MIL, Chapman WG, Vargas FM. Viscosity Modeling of Light Crude Oils under Gas Injection Using One-Parameter Friction Theory. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c04712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yash Khemka
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | | | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Francisco M. Vargas
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- ENNOVA LLC, Stafford, Texas 77477, United States
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Asthagiri D, Chapman WG, Hirasaki GJ, Singer PM. NMR 1H- 1H Dipole Relaxation in Fluids: Relaxation of Individual 1H- 1H Pairs versus Relaxation of Molecular Modes. J Phys Chem B 2020; 124:10802-10810. [PMID: 33185099 DOI: 10.1021/acs.jpcb.0c08078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The intramolecular 1H NMR dipole-dipole relaxation of molecular fluids has traditionally been interpreted within the Bloembergen-Purcell-Pound (BPP) theory of NMR intramolecular relaxation. The BPP theory draws upon Debye's theory for describing the rotational diffusion of the 1H-1H pair and predicts a monoexponential decay of the 1H-1H dipole-dipole autocorrelation function between distinct spin pairs. Using molecular dynamics (MD) simulations, we show that for both n-heptane and water this is not the case. In particular, the autocorrelation function of individual 1H-1H intramolecular pairs itself evinces a rich stretched-exponential behavior, implying a distribution in rotational correlation times. However, for the high-symmetry molecule neopentane, the individual 1H-1H intramolecular pairs do conform to the BPP description, suggesting an important role of molecular symmetry in aiding agreement with the BPP model. The intermolecular autocorrelation functions for n-heptane, water, and neopentane also do not admit a monoexponential behavior of individual 1H-1H intermolecular pairs at distinct initial separations. We suggest expanding the autocorrelation function in terms of modes, provisionally termed molecular modes, that do have an exponential relaxation behavior. With care, the resulting Fredholm integral equation of the first kind can be inverted to recover the probability distribution of the molecular modes. The advantages and limitations of this approach are noted.
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Affiliation(s)
- D Asthagiri
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main Street, Houston, Texas 77005, United States
| | - Walter G Chapman
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main Street, Houston, Texas 77005, United States
| | - George J Hirasaki
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main Street, Houston, Texas 77005, United States
| | - Philip M Singer
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main Street, Houston, Texas 77005, United States
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Sisco CJ, Alajmi MM, Abutaqiya MIL, Vargas FM, Chapman WG. Cubic-Plus-Chain III: Modeling Polymer–Solvent Phase Behavior with the Chain-Modified Cubic Equation of State. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c02483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Mohammed M. Alajmi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | | | - Francisco M. Vargas
- ENNOVA LLC, Stafford, Texas 77477, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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Affiliation(s)
- Yuchong Zhang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
| | - Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
| | | | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
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Singer PM, Valiya Parambathu A, Wang X, Asthagiri D, Chapman WG, Hirasaki GJ, Fleury M. Elucidating the 1H NMR Relaxation Mechanism in Polydisperse Polymers and Bitumen Using Measurements, MD Simulations, and Models. J Phys Chem B 2020; 124:4222-4233. [PMID: 32356986 DOI: 10.1021/acs.jpcb.0c01941] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanism behind the 1H nuclear magnetic resonance (NMR) frequency dependence of T1 and the viscosity dependence of T2 for polydisperse polymers and bitumen remains elusive. We elucidate the matter through NMR relaxation measurements of polydisperse polymers over an extended range of frequencies (f0 = 0.01-400 MHz) and viscosities (η = 385-102 000 cP) using T1 and T2 in static fields, T1 field-cycling relaxometry, and T1ρ in the rotating frame. We account for the anomalous behavior of the log-mean relaxation times T1LM ∝ f0 and T2LM ∝ (η/T)-1/2 with a phenomenological model of 1H-1H dipole-dipole relaxation, which includes a distribution in molecular correlation times and internal motions of the nonrigid polymer branches. We show that the model also accounts for the anomalous T1LM and T2LM in previously reported bitumen measurements. We find that molecular dynamics (MD) simulations of the T1 ∝ f0 dispersion and T2 of similar polymers simulated over a range of viscosities (η = 1-1000 cP) are in good agreement with measurements and the model. The T1 ∝ f0 dispersion at high viscosities agrees with previously reported MD simulations of heptane confined in a polymer matrix, which suggests a common NMR relaxation mechanism between viscous polydisperse fluids and fluids under nanoconfinement, without the need to invoke paramagnetism.
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Affiliation(s)
- Philip M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Xinglin Wang
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Dilip Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - George J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Marc Fleury
- IFP Energies nouvelles, 1 Avenue de Bois-Préau, 92852 Rueil-Malmaison, France
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Valiya Parambathu A, Singer PM, Hirasaki GJ, Chapman WG, Asthagiri D. Critical Role of Confinement in the NMR Surface Relaxation and Diffusion of n-Heptane in a Polymer Matrix Revealed by MD Simulations. J Phys Chem B 2020; 124:3801-3810. [PMID: 32267690 DOI: 10.1021/acs.jpcb.0c00711] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism behind the NMR surface-relaxation times (T1S,2S) and the large T1S/T2S ratio of light hydrocarbons confined in the nanopores of kerogen remains poorly understood and consequently has engendered much debate. Toward bringing a molecular-scale resolution to this problem, we present molecular dynamics (MD) simulations of 1H NMR relaxation and diffusion of n-heptane in a polymer matrix. The high-viscosity polymer is a model for kerogen and bitumen that provides an organic "surface" for heptane. Diffusion of n-heptane shows a power-law dependence on the concentration of n-heptane (ϕC7) in the polymer matrix, consistent with Archie's model of tortuosity. We calculate the autocorrelation function G(t) for 1H-1H dipole-dipole interactions of n-heptane in the polymer matrix and use this to generate the NMR frequency (f0) dependence of T1S,2S as a function of ϕC7. We find that increasing molecular confinement increases the correlation time, which decreases the surface-relaxation times for n-heptane in the polymer matrix. For weak confinement (ϕC7 > 50 vol %), we find that T1S/T2S ≃ 1. Under strong confinement (ϕC7 ≲ 50 vol %), we find that T1S/T2S ≳ 4 increases with decreasing ϕC7 and that the dispersion relation T1S ∝ f0 is consistent with previously reported measurements of polydisperse polymers and bitumen. Such frequency dependence in bitumen has been previously attributed to paramagnetism; instead, our studies suggests that 1H-1H dipole-dipole interactions enhanced by organic nanopore confinement dominate the NMR response in saturated organic-rich shales.
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Affiliation(s)
- Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Philip M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - George J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Dilipkumar Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
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24
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Zhu Y, Bansal A, Xi S, Lu J, Chapman WG. Self-assembly and phase behavior of mixed patchy colloids with any bonding site geometry: theory and simulation. Soft Matter 2020; 16:3806-3820. [PMID: 32242603 DOI: 10.1039/d0sm00248h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Patchy colloids and associating fluids have attracted continued interest due to the interesting phase behavior and self-assembly in solution. The ability to fabricate patchy colloids with multiple attractive surface patches of different number, size, shape, and relative location makes patchy colloids a good candidate as building blocks to form complex advanced materials. However, a theory that clearly relates the self-assembled structures that form based on the anisotropic interactions has been missing. Although Wertheim's theory in the form of the SAFT model is widely used to predict self-assembly and phase behavior in solution, SAFT does not include multibody correlations necessary to model any shape of association site or sites that can form multiple bonds. We have recently developed a new theory for associating colloids that naturally incorporates multibody correlations based on a cluster distribution approach due to Bansal, Asthagiri, Marshall, and Chapman (BAMC). In this paper, we extended the cluster distribution theory to predict the thermodynamic properties and phase behavior of binary systems consisting of anisotropic particles with any geometry of bonding site. In particular, we consider self-assembly of Janus particles, Saturn particles, and ternary particles mixed with solvent colloids that have two directional patchy sites. Good agreement between theoretical predictions and molecular simulation is shown for self-assembly, thermodynamic properties in this system. Re-entrant phase behavior has been investigated and low density gels is predicted.
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Affiliation(s)
- Yiwei Zhu
- Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
| | | | - Shun Xi
- Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
| | - Jinxin Lu
- Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
| | - Walter G Chapman
- Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
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25
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Xi S, Liu J, Valiya Parambathu A, Zhang Y, Chapman WG. An Efficient Algorithm for Molecular Density Functional Theory in Cylindrical Geometry: Application to Interfacial Statistical Associating Fluid Theory (iSAFT). Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.9b06895] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Jinlu Liu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Yuchong Zhang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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26
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Zhang Y, Chapman WG. Modeling Lower Critical Solution Temperature Behavior of Associating Dendrimers Using Density Functional Theory. Langmuir 2019; 35:10808-10817. [PMID: 31335155 DOI: 10.1021/acs.langmuir.9b00514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We study the phase behavior of associating dendrimers in explicit solvents using classical density functional theory. The existence of association enables uptake of solvent inside the dendrimer even for unfavorable Lennard-Jones interaction between the solvent and dendrimer. Depending on the distributions of associating sites, the dendrimer conformation can be either dense-core or dense-shell. The conformation of the associating dendrimer is greatly affected by the temperature. Due to the interplay between association interaction and Lennard-Jones attractions, we find the lower critical solution temperature (LCST) behavior of dendrimer conformation and study how it changes as the dendrimer size or solvent size changes. The dendrimer in our study displays no LCST behavior at low generations, and it has a maximum LCST at G4. Moreover, increasing the solvent chain length decreases the LCST. For solvents with self-association, the competition between solvent-solvent association and solvent-dendrimer association also tends to reduce the LCST. Qualitatively consistent with experiments, our results provide insight into the molecular mechanism of the LCST behavior of associating dendrimers.
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Affiliation(s)
- Yuchong Zhang
- Department of Chemical and Biomolecular Engineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
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27
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Liu J, Xi S, Chapman WG. Competitive Sorption of CO 2 with Gas Mixtures in Nanoporous Shale for Enhanced Gas Recovery from Density Functional Theory. Langmuir 2019; 35:8144-8158. [PMID: 31030516 DOI: 10.1021/acs.langmuir.9b00410] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
CO2 competitive sorption with shale gas under various conditions from simple to complex pore characteristics is studied using a molecular density functional theory (DFT) that reduces to perturbed chain-statistical associating fluid theory in the bulk fluid region. The DFT model is first verified by grand canonical Monte Carlo simulation in graphite slit pores for pure and binary component systems at different temperatures, pressures, pore sizes, and bulk gas compositions for methane/ethane with CO2. Then, the model is utilized in multicomponent systems that include CH4, C2H6, and C3+ components of different compositions. It is shown that the selectivity of CO2 decreases with increases in temperature, pressure, nanopore size, and average molecular weight of shale gas. Extending the model to more realistic situations, we consider the impact of water present in the pore and consider the effect of permeation of fluid molecules into the kerogen that forms the pore walls. The water-graphite interaction is calibrated with contact angle from molecular simulation data from the literature. The kerogen pore model prediction of gas absolute sorption is compared with experimental and molecular simulation values in the literature. It is shown that the presence of water reduces the CO2 adsorption but improves the CO2 selectivity. The dissolution of gases into the kerogen matrix also leads to the increase in CO2 selectivity. The effect of kerogen type and maturity on the gas sorption amount and CO2 selectivity is also studied. The associated mechanisms are discussed to provide fundamental understanding for gas recovery by CO2.
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Affiliation(s)
- Jinlu Liu
- Department of Chemical and Biomolecular Engineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
| | - Shun Xi
- Department of Chemical and Biomolecular Engineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
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28
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Haghmoradi A, Chapman WG. Bond cooperativity and ring formation in hydrogen fluoride thermodynamic properties: A two-density formalism framework. J Chem Phys 2019; 150:174503. [PMID: 31067866 DOI: 10.1063/1.5079874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this work, we develop a thermodynamic perturbation theory using a two-density formalism framework to model the bond cooperativity effect for associating hard sphere and Lennard-Jones fluids. The theory predictions are compared with Monte Carlo simulation results and they are in excellent agreement. We incorporate bond angle dependent ring formation into the theory to calculate hydrogen fluoride thermodynamic properties. The liquid density and vapor pressure obtained by the theory are in good agreement with the experimental data. Comparing the thermo-physical properties of hydrogen fluoride calculated by this theory with previous studies reveals the importance of bond angle dependent ring formation and cooperative hydrogen bonding to capture its anomalous behavior especially in the vapor phase. The cooperativity ratio obtained in our model is close to the values reported by previous quantum studies.
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Affiliation(s)
- Amin Haghmoradi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1892, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1892, USA
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29
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Sisco CJ, Abutaqiya MI, Vargas FM, Chapman WG. Cubic-Plus-Chain (CPC). II: Function Behavior of the Chain-Modified Cubic Equation of State. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Caleb J. Sisco
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- ENNOVA LLC, Stafford, Texas 77477, United States
| | - Mohammed I.L. Abutaqiya
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Francisco M. Vargas
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- ENNOVA LLC, Stafford, Texas 77477, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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30
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Sisco CJ, Abutaqiya MIL, Vargas FM, Chapman WG. Cubic-Plus-Chain (CPC). I: A Statistical Associating Fluid Theory-Based Chain Modification to the Cubic Equation of State for Large Nonpolar Molecules. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00435] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Caleb J. Sisco
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- ENNOVA LLC, Stafford, Texas 77477, United States
| | - Mohammed I. L. Abutaqiya
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Francisco M. Vargas
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- ENNOVA LLC, Stafford, Texas 77477, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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31
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Affiliation(s)
- Xiaoqun Mu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Florian Frank
- Department of Mathematics, Friedrich-Alexander-Universität Erlangen-Nürnberg 91054, Erlangen, Germany
| | - Beatrice Riviere
- Department of Computational and Applied Mathematics, Rice University, Houston, Texas 77005, United States
| | - Faruk O. Alpak
- Shell International Exploration and Production Inc., Houston, Texas 77082, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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32
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Bansal A, Asthagiri D, Chapman WG. A cluster size distribution theory to study the thermodynamics and phase behavior of multi-bonding single site solutes in patchy colloidal mixtures. Soft Matter 2018; 14:7469-7482. [PMID: 30182119 DOI: 10.1039/c8sm01487f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We study binary mixtures of multi-bonding single site solute particles in a solvent comprising patchy colloid particles. The particles in the mixture interact by very short-ranged attraction and hard-sphere repulsion. The attractive patch on the solute can bond with multiple solvent particles, whereas the patch on the solvent is restricted to bond only once. From a quasi-chemical analysis of association, in the hard-sphere reference we develop an accurate multi-body correlation information for the distribution of solvent particles over the patch region of the solute. We use this information within Wertheim's multi-density formalism to develop a cluster size distribution theory that is capable of capturing the physics of multi-body association for any geometry of association sites on the solute. We use this general framework to study a mixture containing Janus solutes and one- or two-patch solvent particles over a range of concentration of the solute and association strengths. We find that a mixture of two-patch solvent (with both patches of the same kind) and multi-bonding solutes with different patch geometries can have a vapor-liquid equilibrium, although the pure components themselves cannot phase separate. The liquid state occurs at very low densities, forming a so-called empty liquid. For the relative association strengths studied in this work, we observe that the vapor-liquid coexistence curve broadens as the concentration of the patchy solvent particles in the liquid phase is increased. The pressure-composition phase equilibrium curves show negative azeotropes for these mixtures. We also observe that, for these mixtures, as the size of the patch on the solute particles is decreased, the critical temperature and the critical packing fraction decreases.
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Affiliation(s)
- Artee Bansal
- Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
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33
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Abstract
Modified inhomogeneous statistical associating fluid theory (iSAFT) density functional theory is extended to dendrimer molecules in solvents of varying quality. The detailed structures of isolated dendrimers in implicit solvent are calculated and have a semi-quantitative agreement with simulation results available in the literature. The dendrimers form dense-core structures under all conditions, while their radius of gyration follows different scaling laws. Factors that affect the quality of the solvent are systematically studied in the explicit solvent case. It is found that the solvent size, density, chemical affinity and temperature all play a role in determining a solvent to be good or poor. New molecular dynamics simulations are performed to validate the iSAFT results. Our results provide insight into the phase behavior of dendrimer solutions as well as guidance in practical applications.
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Affiliation(s)
- Yuchong Zhang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1892, USA
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1892, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1892, USA
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34
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Abstract
Quantifying the statistics of occupancy of solvent molecules in the vicinity of solutes is central to our understanding of solvation phenomena. Number fluctuations in small solvation shells around solutes cannot be described within the macroscopic grand canonical framework using a single chemical potential that represents the solvent bath. In this communication, we hypothesize that molecular-sized observation volumes such as solvation shells are best described by coupling the solvation shell with a mixture of particle baths each with its own chemical potential. We confirm our hypotheses by studying the enhanced fluctuations in the occupancy statistics of hard sphere solvent particles around a distinguished hard sphere solute particle. Connections with established theories of solvation are also discussed.
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Affiliation(s)
- Purushottam D Dixit
- Department of Systems Biology, Columbia University, New York City, New York 10032, USA
| | - Artee Bansal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Dilip Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
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35
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Wang L, Haghmoradi A, Liu J, Xi S, Hirasaki GJ, Miller CA, Chapman WG. Modeling micelle formation and interfacial properties with iSAFT classical density functional theory. J Chem Phys 2018; 146:124705. [PMID: 28388160 DOI: 10.1063/1.4978503] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Surfactants reduce the interfacial tension between phases, making them an important additive in a number of industrial and commercial applications from enhanced oil recovery to personal care products (e.g., shampoo and detergents). To help obtain a better understanding of the dependence of surfactantproperties on molecular structure, a classical density functional theory, also known as interfacial statistical associating fluid theory, has been applied to study the effects of surfactant architecture on micelle formation and interfacial properties for model nonionic surfactant/water/oil systems. In this approach, hydrogen bonding is explicitly included. To minimize the free energy, the system minimizes interactions between hydrophobic components and hydrophilic components with water molecules hydrating the surfactant head group. The theory predicts micellar structure, effects of surfactant architecture on critical micelle concentration, aggregation number, and interfacial tension isotherm of surfactant/water systems in qualitative agreement with experimental data. Furthermore, this model is applied to study swollen micelles and reverse swollen micelles that are necessary to understand the formation of a middle-phase microemulsion.
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Affiliation(s)
- Le Wang
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - Amin Haghmoradi
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - Jinlu Liu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - George J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - Clarence A Miller
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
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36
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Feng Z, Panuganti SR, Chapman WG. Predicting solubility and swelling ratio of blowing agents in rubbery polymers using PC-SAFT Equation of State. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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Abstract
The translational diffusion-coefficient and the spin-rotation contribution to the 1H NMR relaxation rate for methane (CH4) are investigated using MD (molecular dynamics) simulations, over a wide range of densities and temperatures, spanning the liquid, supercritical, and gas phases. The simulated diffusion-coefficients agree well with measurements, without any adjustable parameters in the interpretation of the simulations. A minimization technique is developed to compute the angular velocity for non-rigid spherical molecules, which is used to simulate the autocorrelation function for spin-rotation interactions. With increasing diffusivity, the autocorrelation function shows increasing deviations from the single-exponential decay predicted by the Langevin theory for rigid spheres, and the deviations are quantified using inverse Laplace transforms. The 1H spin-rotation relaxation rate derived from the autocorrelation function using the "kinetic model" agrees well with measurements in the supercritical/gas phase, while the relaxation rate derived using the "diffusion model" agrees well with measurements in the liquid phase. 1H spin-rotation relaxation is shown to dominate over the MD-simulated 1H-1H dipole-dipole relaxation at high diffusivity, while the opposite is found at low diffusivity. At high diffusivity, the simulated spin-rotation correlation time agrees with the kinetic collision time for gases, which is used to derive a new expression for 1H spin-rotation relaxation, without any adjustable parameters.
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Affiliation(s)
- P M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - D Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - W G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
| | - G J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main St., Houston, Texas 77005, USA
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38
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Affiliation(s)
- Xiaoqun Mu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Faruk O. Alpak
- Shell International Exploration and Production Inc., Houston, Texas 77210, United States
| | - Walter G. Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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39
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Heier M, Stephan S, Liu J, Chapman WG, Hasse H, Langenbach K. Equation of state for the Lennard-Jones truncated and shifted fluid with a cut-off radius of 2.5 σ based on perturbation theory and its applications to interfacial thermodynamics. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1447153] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Michaela Heier
- Laboratory of Engineering Thermodynamics, University of Kaiserslautern , Kaiserslautern, Germany
| | - Simon Stephan
- Laboratory of Engineering Thermodynamics, University of Kaiserslautern , Kaiserslautern, Germany
| | - Jinlu Liu
- Chemical and Biomolecular Engineering Department, Rice University , Houston, TX, USA
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering Department, Rice University , Houston, TX, USA
| | - Hans Hasse
- Laboratory of Engineering Thermodynamics, University of Kaiserslautern , Kaiserslautern, Germany
| | - Kai Langenbach
- Laboratory of Engineering Thermodynamics, University of Kaiserslautern , Kaiserslautern, Germany
- Chemical and Biomolecular Engineering Department, Rice University , Houston, TX, USA
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40
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Affiliation(s)
- Yuchong Zhang
- Department of Chemical and
Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Walter G. Chapman
- Department of Chemical and
Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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41
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Bansal A, Chapman WG, Asthagiri D. Erratum: “Quasichemical theory and the description of associating fluids relative to a reference: Multiple bonding of a single site solute” [J. Chem. Phys. 147, 124505 (2017)]. J Chem Phys 2017; 147:199901. [DOI: 10.1063/1.5009414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Artee Bansal
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | - D. Asthagiri
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
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42
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Alasiri H, Chapman WG. Dissipative particle dynamics (DPD) study of the interfacial tension for alkane/water systems by using COSMO-RS to calculate interaction parameters. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.09.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Song J, Zeng Y, Wang L, Duan X, Puerto M, Chapman WG, Biswal SL, Hirasaki GJ. Surface complexation modeling of calcite zeta potential measurements in brines with mixed potential determining ions (Ca2+, CO32−, Mg2+, SO42−) for characterizing carbonate wettability. J Colloid Interface Sci 2017; 506:169-179. [DOI: 10.1016/j.jcis.2017.06.096] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 11/25/2022]
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44
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Liu J, Wang L, Xi S, Asthagiri D, Chapman WG. Adsorption and Phase Behavior of Pure/Mixed Alkanes in Nanoslit Graphite Pores: An iSAFT Application. Langmuir 2017; 33:11189-11202. [PMID: 28859477 DOI: 10.1021/acs.langmuir.7b02055] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The prediction of fluid phase behavior in nanoscale pores is critical for shale gas/oil development. In this work, we use a molecular density functional theory (DFT) to study the effect of molecular size and shape on partitioning to graphite nanopores as a model of shale. Here, interfacial statistical associating fluid theory (iSAFT) is applied to model alkane (C1 - C8) adsorption/desorption/phase behavior in graphite slit pores for both pure fluids and mixtures. The pure component parameters were fit to the bulk saturated liquid density and vapor pressure data in selected temperature ranges. The potential of interaction between the fluid and graphite is modeled with a Steele 10-4-3 potential that is fit to the potential of mean force from single-molecule simulations. Good agreement is found between theory and molecular simulation for the density distributions of pure components in slit pores. The critical properties of methane, ethane, and their mixtures as well as the shift in bubble point and dew point densities were studied, showing good agreement with simulation. The competitive adsorption of mixtures of normal and branched alkanes in graphite pores was also studied. Heavier components more strongly adsorb up to the point that the entropic penalty due to confinement reduces adsorption.
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Affiliation(s)
- Jinlu Liu
- Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States
| | - Le Wang
- Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States
| | - Shun Xi
- Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States
| | - Dilip Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States
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Bansal A, Chapman WG, Asthagiri D. Quasichemical theory and the description of associating fluids relative to a reference: Multiple bonding of a single site solute. J Chem Phys 2017; 147:124505. [DOI: 10.1063/1.4997663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Artee Bansal
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | - D. Asthagiri
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
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Asthagiri D, Valiya Parambathu A, Ballal D, Chapman WG. Electrostatic and induction effects in the solubility of water in alkanes. J Chem Phys 2017; 147:074506. [DOI: 10.1063/1.4997916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- D. Asthagiri
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
| | | | - Deepti Ballal
- Materials Science and Engineering, Ames Laboratory, Ames, Iowa 50011, USA
| | - Walter G. Chapman
- Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005-1827, USA
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Bansal A, Valiya Parambathu A, Asthagiri D, Cox KR, Chapman WG. Thermodynamics of mixtures of patchy and spherical colloids of different sizes: A multi-body association theory with complete reference fluid information. J Chem Phys 2017; 146:164904. [PMID: 28456194 DOI: 10.1063/1.4981913] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We present a theory to predict the structure and thermodynamics of mixtures of colloids of different diameters, building on our earlier work [A. Bansal et al., J. Chem. Phys. 145, 074904 (2016)] that considered mixtures with all particles constrained to have the same size. The patchy, solvent particles have short-range directional interactions, while the solute particles have short-range isotropic interactions. The hard-sphere mixture without any association site forms the reference fluid. An important ingredient within the multi-body association theory is the description of clustering of the reference solvent around the reference solute. Here we account for the physical, multi-body clusters of the reference solvent around the reference solute in terms of occupancy statistics in a defined observation volume. These occupancy probabilities are obtained from enhanced sampling simulations, but we also present statistical mechanical models to estimate these probabilities with limited simulation data. Relative to an approach that describes only up to three-body correlations in the reference, incorporating the complete reference information better predicts the bonding state and thermodynamics of the physical solute for a wide range of system conditions. Importantly, analysis of the residual chemical potential of the infinitely dilute solute from molecular simulation and theory shows that whereas the chemical potential is somewhat insensitive to the description of the structure of the reference fluid, the energetic and entropic contributions are not, with the results from the complete reference approach being in better agreement with particle simulations.
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Affiliation(s)
- Artee Bansal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - D Asthagiri
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Kenneth R Cox
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA
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Singer PM, Asthagiri D, Chapman WG, Hirasaki GJ. Molecular dynamics simulations of NMR relaxation and diffusion of bulk hydrocarbons and water. J Magn Reson 2017; 277:15-24. [PMID: 28189994 DOI: 10.1016/j.jmr.2017.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 05/14/2023]
Abstract
Molecular dynamics (MD) simulations are used to investigate 1H nuclear magnetic resonance (NMR) relaxation and diffusion of bulk n-C5H12 to n-C17H36 hydrocarbons and bulk water. The MD simulations of the 1H NMR relaxation times T1,2 in the fast motion regime where T1=T2 agree with measured (de-oxygenated) T2 data at ambient conditions, without any adjustable parameters in the interpretation of the simulation data. Likewise, the translational diffusion DT coefficients calculated using simulation configurations agree with measured diffusion data at ambient conditions. The agreement between the predicted and experimentally measured NMR relaxation times and diffusion coefficient also validate the forcefields used in the simulation. The molecular simulations naturally separate intramolecular from intermolecular dipole-dipole interactions helping bring new insight into the two NMR relaxation mechanisms as a function of molecular chain-length (i.e. carbon number). Comparison of the MD simulation results of the two relaxation mechanisms with traditional hard-sphere models used in interpreting NMR data reveals important limitations in the latter. With increasing chain length, there is substantial deviation in the molecular size inferred on the basis of the radius of gyration from simulation and the fitted hard-sphere radii required to rationalize the relaxation times. This deviation is characteristic of the local nature of the NMR measurement, one that is well-captured by molecular simulations.
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Affiliation(s)
- Philip M Singer
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main St., Houston, TX 77005, USA.
| | - Dilip Asthagiri
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main St., Houston, TX 77005, USA
| | - Walter G Chapman
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main St., Houston, TX 77005, USA
| | - George J Hirasaki
- Rice University, Department of Chemical and Biomolecular Engineering, 6100 Main St., Houston, TX 77005, USA
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Haghmoradi A, Wang L, Chapman WG. A density functional theory for association of fluid molecules with a functionalized surface: fluid-wall single and double bonding. J Phys Condens Matter 2017; 29:044002. [PMID: 27897149 DOI: 10.1088/1361-648x/29/4/044002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this manuscript we extend Wertheim's two-density formalism beyond its first order to model a system of fluid molecules with a single association site close to a planar hard wall with association sites on its surface in a density functional theory framework. The association sites of the fluid molecules are small enough that they can form only one bond, while the wall association sites are large enough to bond with more than one fluid molecule. The effects of temperature and of bulk fluid and wall site densities on the fluid density profile, extent of association, and competition between single and double bonding of fluid segments at the wall sites versus distance from the wall are presented. The theory predictions are compared with new Monte Carlo simulation results and they are in good agreement. The theory captures the surface coverage over wide ranges of temperature and bulk density by introducing the effect of steric hindrance in fluid association at a wall site.
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Affiliation(s)
- Amin Haghmoradi
- Chemical and Biomolecular Engineering Department, Rice University, Houston, TX, USA
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Gong K, Panuganti SR, Chapman WG. Study of solubility and swelling ratio in polymer‐CO
2
systems using the PC‐SAFT equation of state. J Appl Polym Sci 2017. [DOI: 10.1002/app.44804] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kai Gong
- SINOPEC Exploration & Production Research Institute, Beijing China
| | - Sai R. Panuganti
- Department of Chemical and Biomolecular EngineeringRice University, 6100 Main StreetHouston Texas USA77005
| | - Walter G. Chapman
- Department of Chemical and Biomolecular EngineeringRice University, 6100 Main StreetHouston Texas USA77005
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